In the below configuration, I would like to know whether the NAT only takes place for connections initiated from 30.x network on the inside to 40.x network on the outside OR even the other way round i.e. for connections originated from 40.x network to 30.x network.
ip address 22.214.171.124 255.255.255.0
ip nat outside
ip address 10.10.10.1 255.255.255.0
ip nat inside
ip nat inside source static network 126.96.36.199 188.8.131.52 /24
Instead of destination subnet, I will use the term NAT'd subnet.
The NAT'd subnet will be the representation of the internal subnet for devices facing the outside interface. With that said, connections made from the outside towards 184.108.40.206/24 will be translated to 220.127.116.11/24 in the inside as the router keeps a NAT table for reference.